I have this function that checks for conflicts, but it is not very fast, does anyone have a better sugguestion on how to code this? If I take out the or clauses, it performs fast, but I'm afraid it could allow for conflicts without the other checks.

CREATE FUNCTION ctFun_RoomConflictA  (@RoomID int, @iLength int, @StartTime datetime )  
RETURNS int as 
BEGIN 
     Declare @returnValue int
        select  @returnValue=
	  (select count(meetingnumber) from dbo.meetings
		where (begintime between @StartTime and dateadd(mi,@iLength,@StartTime)
	        or     endtime   between @StartTime and dateadd(mi,@iLength,@StartTime)
	        	or @StartTime between begintime and endtime
	        	or dateadd(mi,@ilength,@StartTime) between begintime and endtime)
	        	and iscancelled=0 and roomid = @RoomID ) 
      return (@returnValue)
END

Thanks

Kirk